Hi Jean, On 22.01.2016 13:50, Jean Delvare wrote: > Hi Christian, > > On Thu, 19 Nov 2015 20:13:46 +0100, Christian Fetzer wrote: >> This is an attempt to upstream the patches created by Thomas Brandon and >> Eddi De Pieri to support the multiplexed main SMBus interface on the SB800 >> chipset. (https://www.mail-archive.com/linux-i2c@xxxxxxxxxxxxxxx/msg06757.html) >> >> I have mainly rebased the latest patch version and tested the driver on a >> HP ProLiant MicroServer G7 N54L (where this patch allows to access sensor data >> from a w83795adg). >> >> The patched driver is running stable on the machine, given that ic2_piix4 is >> loaded before jc42 and w83795. If jc42 is loaded before i2c_piix4 calling >> sensors triggers some errors: >> ERROR: Can't get value of subfeature temp1_min_alarm: Can't read >> >> While the kernel log shows: >> i2c i2c-1: Transaction (pre): CNT=0c, CMD=05, ADD=31, DAT0=03, DAT1=c0 >> i2c i2c-1: Error: no response! >> i2c i2c-1: Transaction (post): CNT=0c, CMD=05, ADD=31, DAT0=ff, DAT1=ff >> Unfortunately I don't know how to tackle this specific issue. > > I think I can explain it. In piix4_setup_sb800() you touch the > SB800_PIIX4_SMB_IDX port without first taking the mutex that protects > it. You only take the mutex on transactions (in piix4_access_sb800) not > during initialization. If self-probing I2C device drivers such as jc42 > are already loaded before you load i2c-piix4, then as soon as the first > SMBus port is registered, i2c-core will try to attach I2C devices to > it, while at the same time i2c-piix4 is registering the second SMBus > port. So SB800_PIIX4_SMB_IDX is changed while piix4_access_sb800 > accesses it and chaos happens. > > I think if we had proper locking in piix4_setup_sb800() then you should > be able to load jc42 first and then i2c-piix4 and it should work fine. > Since the problem remains even after your patch, I'll try to provide more information about the issue. If i2c_piix4 is loaded before jc42 and w83795 things work as they should and sensors prints values from all modules. If w83795 is loaded before i2c_piix4, the w83795adg is not detected. I'm not sure though if this is because of i2c_piix4 or just a shortcoming in the w83795 module. If jc42 is loaded before i2c_piix4 then the problem described above occurs. It seems that jc42 tries to read from all multiplexed ports. This is the full sensors output: jc42-i2c-0-18 Adapter: SMBus PIIX4 adapter SDA0 at 0b00 RAM1 Temp: +26.8°C (low = +0.0°C) (high = +60.0°C, hyst = +54.0°C) (crit = +70.0°C, hyst = +64.0°C) jc42-i2c-0-19 Adapter: SMBus PIIX4 adapter SDA0 at 0b00 RAM2 Temp: +26.5°C (low = +0.0°C) (high = +60.0°C, hyst = +54.0°C) (crit = +70.0°C, hyst = +64.0°C) k10temp-pci-00c3 Adapter: PCI adapter CPU Temp: +30.6°C (high = +70.0°C) (crit = +100.0°C, hyst = +95.0°C) jc42-i2c-1-18 Adapter: SMBus PIIX4 adapter SDA2 at 0b00 ERROR: Can't get value of subfeature temp1_min_alarm: Can't read ERROR: Can't get value of subfeature temp1_max_alarm: Can't read ERROR: Can't get value of subfeature temp1_crit_alarm: Can't read ERROR: Can't get value of subfeature temp1_min: Can't read ERROR: Can't get value of subfeature temp1_max: Can't read ERROR: Can't get value of subfeature temp1_max_hyst: Can't read ERROR: Can't get value of subfeature temp1_crit: Can't read ERROR: Can't get value of subfeature temp1_crit_hyst: Can't read temp1: N/A (low = +0.0°C) (high = +0.0°C, hyst = +0.0°C) (crit = +0.0°C, hyst = +0.0°C) jc42-i2c-1-19 Adapter: SMBus PIIX4 adapter SDA2 at 0b00 ERROR: Can't get value of subfeature temp1_min_alarm: Can't read ERROR: Can't get value of subfeature temp1_max_alarm: Can't read ERROR: Can't get value of subfeature temp1_crit_alarm: Can't read ERROR: Can't get value of subfeature temp1_min: Can't read ERROR: Can't get value of subfeature temp1_max: Can't read ERROR: Can't get value of subfeature temp1_max_hyst: Can't read ERROR: Can't get value of subfeature temp1_crit: Can't read ERROR: Can't get value of subfeature temp1_crit_hyst: Can't read temp1: N/A (low = +0.0°C) (high = +0.0°C, hyst = +0.0°C) (crit = +0.0°C, hyst = +0.0°C) jc42-i2c-2-18 Adapter: SMBus PIIX4 adapter SDA3 at 0b00 ERROR: Can't get value of subfeature temp1_min_alarm: Can't read ERROR: Can't get value of subfeature temp1_max_alarm: Can't read ERROR: Can't get value of subfeature temp1_crit_alarm: Can't read ERROR: Can't get value of subfeature temp1_min: Can't read ERROR: Can't get value of subfeature temp1_max: Can't read ERROR: Can't get value of subfeature temp1_max_hyst: Can't read ERROR: Can't get value of subfeature temp1_crit: Can't read ERROR: Can't get value of subfeature temp1_crit_hyst: Can't read temp1: N/A (low = +0.0°C) (high = +0.0°C, hyst = +0.0°C) (crit = +0.0°C, hyst = +0.0°C) jc42-i2c-2-19 Adapter: SMBus PIIX4 adapter SDA3 at 0b00 ERROR: Can't get value of subfeature temp1_min_alarm: Can't read ERROR: Can't get value of subfeature temp1_max_alarm: Can't read ERROR: Can't get value of subfeature temp1_crit_alarm: Can't read ERROR: Can't get value of subfeature temp1_min: Can't read ERROR: Can't get value of subfeature temp1_max: Can't read ERROR: Can't get value of subfeature temp1_max_hyst: Can't read ERROR: Can't get value of subfeature temp1_crit: Can't read ERROR: Can't get value of subfeature temp1_crit_hyst: Can't read temp1: N/A (low = +0.0°C) (high = +0.0°C, hyst = +0.0°C) (crit = +0.0°C, hyst = +0.0°C) jc42-i2c-3-18 Adapter: SMBus PIIX4 adapter SDA4 at 0b00 ERROR: Can't get value of subfeature temp1_min_alarm: Can't read ERROR: Can't get value of subfeature temp1_max_alarm: Can't read ERROR: Can't get value of subfeature temp1_crit_alarm: Can't read ERROR: Can't get value of subfeature temp1_min: Can't read ERROR: Can't get value of subfeature temp1_max: Can't read ERROR: Can't get value of subfeature temp1_max_hyst: Can't read ERROR: Can't get value of subfeature temp1_crit: Can't read ERROR: Can't get value of subfeature temp1_crit_hyst: Can't read temp1: N/A (low = +0.0°C) (high = +0.0°C, hyst = +0.0°C) (crit = +0.0°C, hyst = +0.0°C) jc42-i2c-3-19 Adapter: SMBus PIIX4 adapter SDA4 at 0b00 ERROR: Can't get value of subfeature temp1_min_alarm: Can't read ERROR: Can't get value of subfeature temp1_max_alarm: Can't read ERROR: Can't get value of subfeature temp1_crit_alarm: Can't read ERROR: Can't get value of subfeature temp1_min: Can't read ERROR: Can't get value of subfeature temp1_max: Can't read ERROR: Can't get value of subfeature temp1_max_hyst: Can't read ERROR: Can't get value of subfeature temp1_crit: Can't read ERROR: Can't get value of subfeature temp1_crit_hyst: Can't read temp1: N/A (low = +0.0°C) (high = +0.0°C, hyst = +0.0°C) (crit = +0.0°C, hyst = +0.0°C) -- To unsubscribe from this list: send the line "unsubscribe linux-i2c" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
